And to the Ocean, I give my Heart
by natcat5
Summary: Matthias has known Niels for nearly as long as he's known the ocean. Both of them constant, unchanging, and ageless. Mermaid AU.


**Originally posted as Part 2 of Dark Month 2015 and Part 2 of Mermaid Week on my AO3.**

/

You are five years old the first time you meet him.

He is stretched out on some rocks by a tide pool, illuminated by the light of the full moon in a cloudless sky. You see his scales glittering, up his back and arms and down to the massive, inhuman tail that trails in the water. Light-coloured hair, damp against his forehead and face, and cold eyes that turn to you with disdain.

"Careful child," he says, "If you get any closer, you may be drowned."

But you are a brave child. Or, foolish, if your nannies are asked. And you clamber out onto the rocks, eyes shining with delight. A fairy creature, on your beach. A merman, here! You can't remember if they are the type of creature you can demand wishes from, or if he'll disappear if you blink too many times in a row. So you hurry, as fast as you can go.

You are very small, and it is hard for you to balance, but you manage to climb close enough to him to see the violet colour of his eyes, the blue-ish tinge to his skin.

You are enraptured; wondrous. You have a thousand questions, you want to touch his tail, you want him to tell you _everything_ about mermaids. You want to sit, and listen, because you love stories, and you're sure his stories will be something fantastic.

But you are five years old, and you are you, and you can't stop yourself from talking, introducing yourself. You have a long title that you love to say. Prince so and so the fourth of this the Duke of that the son of Him and Her and the Heir Apparent to the kingdom of this place and that place over yonder. You can't say it all in one breath, though you always try.

The merman doesn't look impressed by your titles, and that just delights you even more. You wait for him to respond, to tell you _his_ name, to talk, to have a conversation. But his blank stare doesn't change.

"Little Prince," says the merman, "You are so foolish and naïve that even I am not so heartless as to end your life here. Return to your bed and your caretakers; and do not forget that this ocean has teeth, and they do not bow to your crown."

Even young as you are, you can recognize when you've been rebuked, and you wilt a little, hurt. Before you can respond, the merman slides its body off the rocks, into the ocean, and you only see a little of those glittering scales before he disappears entirely.

When you awake in your bed the next morning, you think it must have all been a dream.

/

You are eleven when you meet him next.

You have just been introduced to your betrothed. A princess from another land, whom you have been engaged to since birth. She is older than you by a year, and is unimpressed by all your attempts to impress her with your budding sword skills and your collection of maritime books and sea shells. You wanted to take her walking along the beach, a pastime you have always been fond of, but she declined, and is instead taking tea with your mother. You are walking alone.

It is evening; twilight. The seaside wing of the castle faces west, and the sun is sinking into the waves in such a way that paints the whole ocean orange, yellow, red. It's beautiful.

The light is dimming rapidly, however, and when you see a figure collapsed on the beach a little further up, by some rocks, you think it must be a trick of the light.

You quickly realize it isn't.

Even now, close to adolescence, you are a child with your head in the clouds. You are airy, foolish, impulsive, and veering dangerously close to simple; or so you've frequently been told. Your interest in the sea is appreciated only when it's turned towards learning of maritime trade and naval battles. Your love of the creatures that dwell within it is seen as a distracting fancy. You've made an effort to be less consumed by it, now that you're past ten.

You thought the merman was a dream.

But here he is again, sprawled out on the sand, skin looking more purple then blue in the light of the sunset. Scales glittering, just as you remember them.

You cannot possibly be dreaming now.

His eyes are closed when you kneel next to him, and here, with the sun still present, and none of the mists and illusionary fogs that nighttime brings, he looks terrifyingly real. The strands of hair, damp against his face. The lines of muscles along his arms and stomach. The discoloured patches of skin, blue and a darker purple, like bruises, littering his torso.

You reach out to touch him just to be sure.

Your fingers barely ghost against his skin, but the reaction is immediate. His eyes fly open and he sits up abruptly, causing you to squeak in surprise and tumble back.

The merman's eyes are flat, his nostrils flaring, and the difference in size between the two of you is suddenly terrifyingly apparent. His tail alone is as long as you are tall. Your heart pounds, and you are afraid.

A tense moment passes between you, before the merman blinks, tilting his head.

"Oh," he says, voice devoid of emotion, "It's Prince Mathias Kohler the fourth of Denmark, Duke of Lolland, son of King Christopher and Queen Annalise, Heir Apparent to the Kingdoms of Denmark, Norway, and Iceland. Still walking by yourself at night, are you?"

You are startled by the frankness of his address. You are startled because him speaking to you just affirms that he is _real,_ that he is _here._ You are startled because he has remembered every one of the titles that you babbled at him six years ago.

"You remember me!" you exclaim, overtaken with delight.

"Despite my best efforts," replies the merman dourly, "A lack of self-preservation such as yours is hard to forget. Particularly as it seems prone to repetition."

You recall, vaguely, that your last meeting ended with him imparting some kind of warning upon you. But you cannot remember what it was, nor can you imagine it to still be relevant, six years later.

And regardless, you are swept up in a tide of childish joy. The stories you love, the wild sea, with all of its wonders and secrets. Everything you're being told to grow out of, now that you're officially in courtship. Now that you are well and truly en train to the throne.

You've been so good for the duration of your bethrothed's visit. So quiet. In the emptiness of the beach, with only you and a being from your wildest dreams, you let your true self bubble forth. You babble, you talk, you ask questions and move on to the next one without waiting for an answer. You compliment his scales and ask why he's here and forget to pause for breath before moving on to the next thought. You can barely keep up with your own words, tongue tripping in your haste.

The merman looks faintly amused, you think. And when you finally pause for breath, he fixes you with a look you cannot place.

"You are so happily curious about merpeople, because you truly don't know anything about them," he says, "Little Prince, my kind and yours were not meant to mingle, nor cross paths. We are best kept separate, with your questions unanswered."

It's not what you want to hear, and you say as much, pouting. You've crossed paths _twice_ now, and that means something, surely?

The sun has nearly sunk, and the merman's figure is shadowed, eyes glinting in the fading light. "It merely means we both must be more careful in the future," he says, "And that it is time for me to take my leave."

The merman begins the process of shuffling down the beach, a strangely inglorious movement. But at the same time, intimidating, the chords of muscles on his arms standing out as he pushes himself. The massive tail flexing against the sand.

He doesn't have a long way to go, and you follow helplessly after, watching as he reconnects with the surf. Wondering why he was lying there asleep anyways.

"Can't I get your name, too?" You shout out as the waves crash over his body, the shimmering purple of his body fading into the shifting ocean.

You see him turn, look back, but if he says anything, it's lost to the crashing of the waves.

And then he's gone.

/

You are fourteen, and at sea.

You have finally been allowed to go out sailing alone, and you are in your element, ecstatic with the freedom. The waves, the breeze, the salt and the water; they refresh and invigorate you in ways you can't possibly explain.

The boat is small, manageable by one man, and the bodyguard and aide they've sent with you is asleep under the prow. It's easy to forget he's there. To pretend you're alone. You are enjoying your time free of the palace, free of all the responsibilities that ensnare you when you are within its walls.

It's midday, bright and sunny, and when you catch glimpses of something glittering in the water, you think it must be a trick of the light.

It is not a trick of the light.

His shimmering scales are the same, though you can articulate their beauty a bit better now. Cobalt, indigo, a lighter shade close to amethyst. The blue tinge of his skin something akin to aquamarine, until such time as the light hits it just right, and casts it in a hue closer to the violet colour of his eyes.

Considering your last parting, years prior, you're not expecting him to pop his head out of the water and look at you. Float beside your boat looking for all the world like he wishes to hold a conversation.

But, astonishingly, that appears to be the case.

"It occurred to me that I have been rude," says the merman, in that glib, flat voice you remember, "It is possible that you saved my life when you found me on the beach and woke me up in time for me to return to the ocean, before anything else with more intelligence had found my sleeping form. I've thought about it, and decided that a thank you is probably appropriate in this situation."

You blink. His eyes are locked with yours. This is the first time you've seen him in the light of day, the first time you're looking at his face clearly. Pale hair, violet eyes, looking like he could be younger than your father, perhaps only a handful of years older than you.

"Wh- that happened three years ago!" you splutter, rushing over to the edge of the boat to see him better, "You're thanking me _now?_ And, hey, what was that bit about intelligence? You know, I think that's a bit of a backhanded way to thank someone, wouldn't you say? Also, how did you know this is my boat? Do you watch the coast? Do you live around here? Wh-,"

The merman disappears beneath the waves, sending a shower of water splashing into your face. You splutter and pull away from the edge, wiping the salty spray out of your eyes.

When you finally clear your vision, he's gone, and your stomach sinks. More years of unanswered questions in your future.

Then you hear a splash from behind you, and whirl around.

"The years don't pass the same for you and I," says the merman, having reappeared near the bow, arms resting on the edge of the boat. "I suppose that deserves answering. Your human years are inconsequential; I don't notice them passing. It was not my intention to have waited so long before action and thanks."

It takes you a moment to gather your thoughts, and when you do, you try to organize them in a way that won't have you babbling uncontrollably again. He may disappear the second you take your eyes off him. You need to make your questions _count._

"I'd still like to know your name, if you'll allow it," you say, concentrating to stop your words from tumbling out in a rush, "And if you'll answer some questions I have, have always had, about the world beneath the surface."

Something flashes in the merman's eyes, and it tilts its head to the side, a gesture that you remember.

"You humans know enough of my kind," he says flatly, "Enough for most of you, those with sense at least, to know that correspondences like this are hazardous."

"Your kind exist only in fables to my people," you say, breathless and struggling to speak slow, nearly overtaken with the fact that you're _having a conversation._ "Storybooks. Nothing known there could be considered fact. You are barely believed to be real. And I _do_ have sense! What's with you and insulting my intelligence?"

The merman looks faintly amused, droplets of water dripping from its hair, rolling down its nose.

"Some things are better left to stories," he says, his tone unreadable. He says nothing else, and there's mirth in his eyes, as he watches you wait for him to answer the question about your intelligence, and grow more and more impatient.

"Fine," you huff, "That's- whatever, I don't even care. Just, but please, just-,"

You attempt to sound less whiny, less young, less like an unintelligent child, as you match your eyes with his.

"Your name," you ask again, "You know mine, and this is our third meeting, please."

The gaze that the merman affixes you with now is weightier than all the others have been, and you quail under it. You are suddenly aware, acutely so, of the age difference between you. His appearance is deceiving; you're sure he's looked the same in the near ten years that you've known him. He is old, he is possibly ancient.

"I go by Niels, in some waters," the merman answers after a stretch of silence, surprising you, "And worry not, Little Prince, this will be the last of our meetings."

And in a spray of water, a glimmer of light on his scales, he's gone.

/

It is not your last meeting.

You are nineteen, nearly twenty, and you are sailing home from your wife's homeland, where you have been visiting. Your ship is caught in a storm, and despite the captain's wishes, you have chosen not to remain below with your wife in your quarters, but to assist on deck.

In the past few years, you have become an accomplished sailor. Every spare moment has been spent out on the waves, enjoying the freedom of the ocean, and secretly hoping for Niels to reappear. You sail your own, small boats mostly. But you are capable of manning a larger ship, and you cannot allow yourself to remain below when you can help the crew wrestle through the storm.

After the first hour of battle, you can see that the captain is glad for your assistance. You know your way around, and you are instrumental in helping to coordinate the crew, in the handling of the ropes, the movement of the ballast, and navigating the chaos of a storm-ravaged deck.

But even you, Prince of Denmark, cannot bring order to the weather. And the waves begin to swamp the deck. You begin to lose men, swept overboard before they can even scream. It's impossible to keep your footing, and everyone goes sliding. The captain shouts something, orders, or perhaps your name, but it is lost to the roaring of the storm.

Another wave. This one catches you, sprawled against the rail as you are, and you find yourself in the air, and then, in the water, devoid of air.

The impact and the cold is too much for your already exhausted body and you can't find the strength to fight the sea as it swallows you. Your eyes shut.

When you open them again, it's because something is spiritedly slapping at your face, and as you open your mouth to protest, a disgusting fountain of water and vomit emerges instead.

You roll onto your side, heaving, and feel someone pound against your back, none to gently.

When you've exhausted the contents of your stomach and lungs, you roll back onto your back, gasping. You feel a touch against your face, someone brushing your hair back away from your eyes, and you blink, feeling grit and seasalt crusting your eyelids.

It takes a few tries to clear it away, and when you do, the glare of the sun has you squinting. The figure leaning over you is impossible to make out, it's so blurred, and you try to call out, to ask their identity. But all that emerges from your mouth is a dry croak, throat scoured by seasalt and stomach acid.

"Quiet, idiot," says the figure above you, voice familiar, "Your people will find you. I've nothing better to do, so I'll sit with you until they come down this way. Until then, try not to talk and waste what little energy you have left. The nerve of you, trying to swallow all of my ocean like that."

You're startled into a laugh, despite his admonitions. It's a harsh sound, and your chest hurts. You hear him tsk, and fight to open your eyes again.

This time, you succeed, though the image is blurred by your exhaustion. It's Niels, it is most certainly Niels. Even in the dim light, you can see his violet eyes, the shimmer of scales, the flaxen hair, hanging damply in front of his face. He's closer to you than he's ever been before, and you are struck, suddenly, by the fact that he's handsome.

"Hey," you say, ignoring the irritated look Niels gives you, "I think we're about the same age now, aren't we?"

His expression flattens suddenly, into something guarded, and tangibly old. You're not surprised at the answer he gives you, distant and aloof.

"No, Little Prince, we are not," he says, "And we never shall be. You and I are worlds away."

You're not hurt by the answer, you understand it in fact, and you fall silent, satisfied. Your body aches, and you're exhausted, and cold. There's a warmth radiating outwards from Niels's body, and it's comforting, where his tail is pressed against your legs, the feeling of his breath against your face.

Distantly, in the faded edges of your vision, you can see the sun, rising against the horizon. It's dawn, and the storm is over.

With your merman watching over you, your consciousness fades away.

/

You are thirty-three, and have not seen Niels since you nearly drowned, over ten years ago.

You are walking along the beach with your two daughters, both of them running ahead. Their mother never became inclined to join you in your love of the sea, especially after it nearly killed you, but your children are like you, and are called by it.

Your youngest stops to collect seashells, entranced by the variety of colours. Your oldest dances in the waves, crafting a dress of seafoam and laughing in delight. You smile as you watch them.

Out of the corner of your eye, you see something shimmer in the water. A strange shade of blue, almost purple, glittering in the sun. Your head turns sharply towards it, but your eyes see nothing but the shifting waves. It is not the first time that this has happened.

You know you were not dreaming. Not four times, over such a span of years. You know he's real. You know he saved your life.

But sometimes, you can't help but wonder.

/

You are forty-two, and your wife is dead.

There is nothing that could be done, the doctors said. The disease would run its course, and all anyone could do was make sure that her last days were comfortable.

Now she is dead, the funeral has passed, and your feet have carried you away from your palace and empty rooms. Down the familiar path to the beach, the rocky coast that you have loved since you were a little boy.

You are not as young and spry as you once were, and it takes more concentration to maneuver your way through the rocks close to the waves, but you find yourself a spot. A sandy, dry place, where you can sit and rest your back against a rock. Close enough to the ocean to feel the spray, the smell of salt and the sound of the waves strong in the air.

"I could never convince her to come down here with me," you say aloud, reminiscing to no one but the breeze, "I was never able to share this with her."

The waves crash against the shore. Your cheek is dampened, and you blink against the droplets gathering on your lashes.

"Not everyone is born with the sea in their blood, as you were," says a familiar voice, from the other side of the rocks, "Most find it fearsome. In a species lacking the capabilities to survive the wilds of the ocean, it is only the fools who are drawn to it."

"All these years, and that's the first thing you say?" you respond wryly, not bothering to ask for the speaker's identity, "But I suppose that's how I know it's you. Belittling my intelligence the first chance you get."

"You've given me little cause to do otherwise," he replies, and you can hear the amusement in his voice. It soothes some of the ache in your chest.

You have vacillated between believing your merman to be a dream, a hallucination, and being certain he is real, in the past years. But as much as logic, as facts and common sense dictated otherwise, you could never quite believe that he had been a figment of your imagination. No, for all your wavering and doubt, you never truly thought that Niels hadn't been real.

"My wife is dead," you say abruptly, "I'm not entirely sure what to do myself. I mean, I know I have a kingdom to run and everything, but still…"

Your words trail off, you feel listless and tired. The sea breeze feels colder than it used to.

A shower of water splashes down on the top of your head, and you look up, blinking as it drips into your eyes.

Niels is looking down at you, arms folded on top of the rock you are leaning against. He is the same as always. Pale hair, wet against his face, and violet eyes. He looks young to you now, which is terrifying. His face seems round and his skin distinctly unlined. It's only his eyes that carry age. That seem ancient, and older than you still.

"You have your daughters," he says, in a voice uncharacteristically soft, "And they love the sea as you do. Walk with them on the mornings you'd rather lie in bed, the days you'd rather do nothing. You've managed to keep that figure for this long; it'd be a shame if you grew fat now."

You can't quite muster a laugh, but you smile a little, comforted by Niels's familiarly back-handed advice.

"Do you ever speak with them?" you ask, "My daughters?"

"No," answers Niels flatly, and then, after a moment's hesitation, "But sometimes I leave them seashells."

He sounds embarrassed by it, cheeks a little red. You do laugh then, loud and genuine, because Niels, for all his warnings, all his insults, is as taken with humans as you are with the ocean. It's taken you near forty years, but finally, you've seen right through him.

/

You are fifty-five years old.

You saw Niels much more frequently after that day on the beach following your wife's death. Nothing regular, of course, but if you sat down on some rocks by a tide pool, or stared out at the waves on a calm full moon, chances were Niels would pop by, unchanging as always. Sometimes with new shells for your daughters, and granddaughters. Sometimes with nothing but sarcasm and insults.

He always looks the same as he did when you were five. It makes your age, visible as it is, feel that much more daunting.

You have never been one to let your age slow you down, even though your own parents died just past sixty, and you lost your wife before she reached fifty. Your daughters fuss, but you're not a feeble old man yet. You've still got your wits about you, and a spring in your step, and-

Well, perhaps a bit too much spring.

You slip, as you walk across the rocks on your beach. Hit your hip painfully, can't galvanize your reflexes into action before your head smacks against the uneven ground.

 _This is very embarrassing,_ you think, vision completely whited out, pain throbbing throughout your body, _this is the type of kingly death that young princes laugh about. My son-in-law is literally going to piss himself._

Your son-in-law is a prick. He'll be a good king, but he is a prick and you regret not telling him that to his face.

Oh, but you did tell him that. The memory is hazy, but you're certain that after you had a bit too much wine during your youngest daughter's marriage you decided to be honest and tell your oldest daughter's husband just what you thought of him.

He had been a good sport about it. You don't dislike him, even if he is a prick. He'll serve the kingdom well. And since you've evidently already told him what you think of him, you don't have any regrets, sprawled out on the beach with your brains dashed against the rocks.

Your thoughts, your memories, they all begin to slip away, whited out like your vision. And you feel the throbbing pain subside into a distant ache, and then, to nothing at all. The noise of the sea fades into something fuzzy and unidentifiable, and then into nothing, into silence.

"You are unbelievable."

Your eyes fly open.

Niels is in front of you, lower half in the waves, upper half on the sand and rocks, arms folded underneath him. He looks cross, moreso than usual. Not the usual look of disdain, contempt. But one that is genuinely upset, something dangerously close to sadness or hurt in his eyes.

"Oh, well," you reply, smiling nervously, "These things happen sometimes. You mustn't fault an old man for losing some of his grace and poise with age."

Niels shakes his head, looking exasperated. It's the most expressive you've seen him in all the time you've known him.

It occurs to you, in a distant sort of way, that your thoughts are very clear, and very sharp. That you're speaking easily, and that the fog that had been descending over you has disappeared entirely. You worry about it, for half a second, before that thought slips away.

"I can't think of any other king in history who this would happen to," says Niels, sounding disgusted, "Honestly, Little Prince, I don't know what I'm to do with you."

He shakes his head again, and you smile sheepishly. He rolls his eyes.

"Anyways," he says, fixing his gaze on you once more, "Are you coming or what?"

He has extended one hand towards you, skin purple-tinged where it is not covered in glimmering scales. Familiar; a hand you've known for fifty years.

You extend your own hand to take his, and are somehow not surprised to see patterns of red and orange dappling your own skin. Travelling down your arm to your torso.

 _So this is how these things go,_ you muse, even as your memories begin to fade. Even as the kingdom you're leaving behind dulls to an afterthought.

You take Niels's hand, and follow him into the sea that you love so much, have always loved. You follow the arc of his beautiful blue-purple tail, your own red-gold one flashing in the sun behind.

On the beach, you leave the crumpled body of an old, human, man. His life over, and a new one just begun.


End file.
